Solvent abuse is a growing public health problem in the United States and elsewhere, particularly among young adults and adolescents. Inhalation of toluene-based products, such as spray paint or glue, is popular with solvent sniffers because of euphoric effects and easy availability of these substances. While neurologic sequelae have been reported from long-term abuse of such products, systematic analysis of the neurologic involvement in a large population of such individuals has not been carried out. Based on preliminary data and a large population of toluene abusers available for evaluation, we plan the following studies: (1) Detailed solvent abuse history attemtping to quantitate cumulative dose of toluene; (2) Quantitative neurological examination and disability status scale; (3) Detailed neuropsychological testing; (4) Evoked potential testing (including visual, brainstem auditory, and somatosensory evoked responses); (5) Tremor analysis; and (6) Magnetic resonance imaging (MRI) of the brain. The data obtained from these studies should enable us to detect the earliest involvement of the central nervous system (CNS) from toluene abuse and help to establish a dose-response relationship between exposure and CNS toxicity. It is also hoped that a single test will emerge as being the most sensitive indicator of CNS involvement which can then be used as a useful screening tool for detection of CNS disease. The information gained from such studies will likely aid in the management of toluene and other solvent abusers as well as help in the study of individuals chronically exposed to low levels of solvents in industrial settings who also develop CNS involvement.